Anhydrous pigment paste and its use in cosmetics

ABSTRACT

The invention relates to an anhydrous pigmentary paste comprising:  
     from 20 to 32% by volume of at least one solid pigment, with respect to the total volume of the pigmentary paste,  
     a pigment dispersion medium containing at least one anhydrous solvent selected from the hydrocarbon oils and the silicone oils, and  
     a dispersing agent containing at least one imide or succinimide group linked by a covalent bond to a polymer chain compatible with the dispersion medium.

[0001] The present invention relates to an anhydrous pigmentary pastefor colouring cosmetic compositions, comprising solid pigments,dispersed in a continuous medium by a dispersing agent.

[0002] By pigmentary paste should be understood a concentrated colloidaldispersion of pigments in a continuous medium, or dispersion medium,stabilized by a dispersing agent, or without a dispersing agent.

[0003] A concentrated colloidal dispersion should be understood to meana suspension of particles of micron size, in other words less than 10μm, in a continuous medium. The volume fraction of particles in aconcentrated dispersion is of the order of 20 to 40%, preferably greaterthan 30%. Any liquid required for the dispersion may take the place ofthe continuous medium, for example water, glycol, solvents, fats andtheir mixtures.

[0004] The dispersing agent protects the dispersed particles againstagglomeration or flocculation. The dispersing agent may be asurface-active agent, an oligomer, a polymer or a mixture of a number ofthese, bearing one or more functional groups with a strong affinity forthe surface of the particle to be dispersed.

[0005] These pigments are difficult to disperse in hydrocarbon oils orsilicone oils, conventionally used in lipsticks, and tend toagglomerate, even in the presence of conventional dispersing agents.This limits the maximum concentration of pigments in the oil, andimpairs the fluidity of such a dispersion.

[0006] The use of dispersing agents in pigmentary pastes is known in theprior art. However, the pigmentary pastes containing these organicpigments in the presence of a conventional dispersing agent arerelatively thick and have high viscosity, causing the dispersing agentto have a poor adsorption affinity for the surface of the organicpigments.

[0007] The object of the invention is thus a pigmentary paste whichovercomes the disadvantages of the prior art.

[0008] The object of the invention is in particular an anhydrouspigmentary paste containing a dispersing agent with a good adsorptionaffinity for the surface of the pigments, particularly that of organicpigments. The presence of such an agent has the advantage of creatingthe possibility of producing pigmentary pastes with low viscosity, whilemaintaining a high concentration of pigments.

[0009] A further object of the invention is the use of an anhydrouspigmentary paste according to the invention to colour cosmeticcompositions, and in particular lipsticks.

[0010] A further object of the invention is a cosmetic compositioncontaining a cosmetically acceptable medium and a pigmentary pasteaccording to the invention.

[0011] In the context of this application, cosmetically acceptable meansa composition with a pleasant appearance, odour, taste and feel.

[0012] The objectives of the present invention are achieved by producingan anhydrous pigmentary paste comprising:

[0013] from 20 to 32% by volume of at least one solid pigment, withrespect to the total volume of pigmentary paste,

[0014] a pigment dispersion medium containing at least one anhydroussolvent selected from the hydrocarbon oils and the silicone oils, and

[0015] a dispersing agent which is a polymer containing at least oneimide or succinimide group linked by a covalent bond to a polymer chaincompatible with the dispersion medium.

[0016] The imide or succinimide group or groups may be side or endgroups, preferably end groups.

[0017] Compatible polymer chain means a polymer or oligomer chainsoluble in the continuous phase of the dispersion.

[0018] The polymer advantageously has a molecular weight of at least 600g, and preferably from 1000 to 1500 g.

[0019] The preferred polymer chains according to the invention are thepolyolefins, such as the polyethylenes, the polypropylenes and thepolyisobutylenes and other poly α-olefins. The particularly preferredpolymer chains are the polyisobutylenes.

[0020] The dispersing agents which may be used according to theinvention are preferably polymers obtained by condensation of an aminewith a succinic anhydride having a saturated or unsaturated hydrocarbonchain, whose synthesis is disclosed in the patent U.S. Pat. No.3,172,892. The preferred dispersing agents are polyisobutylenescontaining at least one succinimide group, preferably a terminalsuccinimide group. These dispersing agents advantageously have a polymerchain of molecular weight of at least 600 g, and preferably from 1000 to1500 g. Such dispersing agents are disclosed in the U.S. patents U.S.Pat. No. 3,172,892 and U.S. Pat. No. 3,235,484, and are known under thename of LUBRIZOL™. A particularly preferred dispersing agent is thepolyisobutylene succinimide marketed under the trade name LUBRIZOL™0517134.

[0021] The dispersing agent generally represents from 1 to 10% of thetotal weight of the pigmentary paste, and preferably of the order of 5%.

[0022] The pigmentary paste according to the invention also contains apigment normally used in cosmetic or dermatological compositions.

[0023] The pigments which may be used according to the invention may beinorganic or organic, white or coloured, or nacres, or their mixtures.

[0024] The inorganic pigments include titanium dioxide, optionallysurface-treated, or zinc dioxide, zirconium or cerium oxides, and theiron and chromium oxides, manganese violet, ultramarine blue, chromiumhydrate and ferric blue, and their mixtures. The preferred inorganicpigments are the iron oxides, especially red iron oxide, yellow ironoxide, red and yellow iron oxide, brown iron oxide, black iron oxide,titanium dioxide and their mixtures.

[0025] The organic pigments include:

[0026] the pure organic pigments, such as carbon black or those whichmay or may not have a FDA certification, such as D&C Red No 36, and

[0027] the pigments of the organic lake type, such as the organic lakesof barium, strontium, calcium or aluminium with a FDA certification orexempt from FDA certification such as the lakes based on cochinealcarmine, D&C Red No 7 calcium lake, D&C Red No 27 aluminium lake, D&CRed No 21 aluminium lake, FD&C Yellow No 5 aluminium lake, FD&C YellowNo 6 aluminium lake, D&C Red No 7 and FD&C Blue No 1 aluminium lake, andtheir mixtures.

[0028] The nacre pigments may be selected from the white nacre pigments,such as mica coated with titanium or bismuth oxychloride, the colourednacre pigments such as titanium mica with iron oxides, titanium micawith in particular ferric blue or chromium oxide, titanium mica with anorganic pigment of the type mentioned above.

[0029] The dispersing agent according to the invention has a goodaffinity for the surface of the pigments, and especially the organicpigments.

[0030] The dispersion medium of the solid pigments contains at least oneanhydrous solvent selected from the hydrocarbon oils and the siliconeoils. These oils may be polar or non-polar oils, volatile ornon-volatile, usable in cosmetics.

[0031] The polar oils include the hydrocarbon oils containing ester,ether, acid or alcohol functions or their mixtures, such as for example:

[0032] the plant hydrocarbon oils with a high content of triglyceridesconsisting of esters of fatty acids and glycerol, of which the fattyacids may have varying chain lengths and may be linear or branched andsaturated or unsaturated; these oils particularly include wheat germ,corn, sunflower, shea, sweet almond, macadamia, apricot, soya, rapeseed,cotton, alfalfa, poppy, pumpkin, sesame, marrow, avocado, hazelnut,grapeseed, blackcurrant, evening primrose, millet, barley, quinoa,olive, rye, safflower, bancoulier, passion flower, rose hip oils, orcastor oil; or triglycerides of caprylic/capric acids such as thosemarketed by the Company Stearineries Dubois or those marketed under thetrade names Miglyol™ 810, 812 and 818 by the Company Dynamit Nobel, thesynthetic oils of formula R¹COOR² in which R¹ represents a linear orbranched higher fatty acid residue, containing from 7 to 19 carbonatoms, and R² represents a branched hydrocarbon chain containing from 3to 20 carbon atoms, such as for example Purcellin oil (ketostearyloctanoate), isononyl isononanoate, the C₁₂ to C₁₅ alcohol benzoates.

[0033] the synthetic esters and ethers such as isopropyl myristate,2-ethylhexyl palmitate, the octanoates, decanoates or ricinoleates ofalcohols or polyalcohols,

[0034] the hydroxyl esters such as isostearyl lactate, diisostearylmalate, and the pentaerythritol esters;

[0035] the C₈ to C₂₆ fatty alcohols such as oleic alcohol ; and theirmixtures.

[0036] The anhydrous solvent is preferably an apolar oil.

[0037] The apolar oils include:

[0038] the silicone oils which may be volatile or non-volatile, linearor cyclic, liquid at ambient temperature, such as thepolydimethylsiloxanes (PDMS) containing alkyl, alkoxy or phenyl groups,pendant or at the end of the silicone chain and having from 2 to 24carbon atoms; the phenylated silicones, such as the phenyltrimethicones, the phenyl dimethicones, the phenyl trimethylsiloxydiphenylsiloxanes, the diphenyidimethicones, the diphenyl methyldiphenyltrisiloxanes, the 2-phenylethyl trimethylsiloxysilicates, and theirmixtures.

[0039] the hydrocarbons or fluorinated hydrocarbons, which may be linearor branched and of synthetic or inorganic origin, such as the paraffinoils (for example the isoparaffins), and the aliphatic hydrocarbonswhich may be volatile (for example isododecane), or non-volatile andtheir derivatives, vaseline, the polydecenes, hydrogenated polyisobutenesuch as Parleam™, squalane, and their mixtures.

[0040] The anhydrous solvent is preferably an apolar hydrocarbon oil, ofsynthetic or inorganic origin, selected in particular from thehydrocarbons, especially alkanes, such as Parleam™ (hydrogenatedpolyisobutene), isoparaffins including isododecane, squalane, and theirmixtures. The particularly preferred anhydrous solvent is Parleam™(hydrogenated polyisobutene).

[0041] The pigmentary pastes according to the invention generally have aviscosity of from 2 to 25 Poises (0.2 to 2.5 Pa.s), preferably 10 Poises(1 Pa.s) or less, and more preferably 5 Poises (0.5 Pa.s) or less, theviscosity being evaluated at ambient temperature (20 to 25° C.), with ashearing rate of 200 s⁻¹, using a Rhéomat RM 180 viscometer with mobiles2 or 3 depending on their suitability for the viscosity of thepigmentary paste.

[0042] The pigmentary pastes according to the invention are particularlysuitable for colouring cosmetic compositions, and especially in theformulation of lipsticks.

[0043] The following examples illustrate the invention without in anyway limiting its scope.

[0044] In the examples, except where otherwise stated, all quantitiesare expressed as weight fractions with respect to the total weight ofthe pigmentary paste.

EXAMPLES

[0045] The pigmentary pastes PP1 to PP5 according to the invention wereprepared by mixing the ingredients listed in table 1 below as follows:

[0046] 1. the dispersing agent was dissolved in Parleam™, at atemperature of about 80° C., over 10 to 15 minutes, so as to ensurecomplete dissolution of the dispersing agent;

[0047] 2. the pigments were then progressively added to Parleam™ withstirring by a deflocculant disk, to ensure complete mixing of thepigments, then the mixture was homogenized for about 15 minutes;

[0048] 3. this mixture was then milled in a DISPERMAT grinder for 35 to40 minutes, at a temperature of 25 to 30° C.

[0049] For each pigmentary paste PP1 to PP5, the viscosity was measuredat ambient temperature (20 to 25° C.) with a shearing rate of 200 s⁻¹,with a Rheomat RM 180 viscometer with mobiles 2 or 3 depending on theirsuitability for the viscosity of the pigmentary paste.

[0050] The results of the viscosity measurements for the pigmentarypastes PP1 to PP5 are given in table 2. TABLE I composition (%) PP1 PP2PP3 PP4 PP5 D & C Red No 36 40% 40% — — — (26.1% by volume) D & C Red No7 — — 30% 30% 40% Parleam ™ 57% 55% 67% 65% 55% LUBRIZOL  3%  5%  3%  5% 5% OS17134AZ

[0051] TABLE 2 PP1 PP2 PP3 PP4 PP5 viscosity 6 4.8 6.7 2.7 13.2 [Poise]

[0052] Table 2 shows that the pigmentary pastes according to theinvention PP1 to PP5 have low viscosity, in other words lower than 15Poises, for a high weight fraction of pigment.

[0053] Table 2 also shows that, for the same quantity of pigment, anincrease in the weight fraction of dispersing agent leads to a furtherdecrease in the viscosity.

1. Anhydrous pigmentary paste comprising: from 20 to 32% by volume of atleast one solid pigment, with respect to the total volume of pigmentarypaste, a pigment dispersion medium containing at least one anhydroussolvent selected from the hydrocarbon oils and the silicone oils, and adispersing agent which is a polymer containing at least one imide orsuccinimide group linked by a covalent bond to a polymer chaincompatible with the dispersion medium.
 2. Pigmentary paste according toclaim 1, characterized in that the polymer chain has a molecular weightof at least 600 g
 3. Pigmentary paste according to claim 1 or 2,characterized in that the polymer chain has a molecular weight of from1000 to 1500 g.
 4. Pigmentary paste according to any of the precedingclaims, characterized in that the polymer chain is a polyolefin. 5.Pigmentary paste according to any of the preceding claims, characterizedin that the polymer chain is a polyisobutylene.
 6. Pigmentary pasteaccording to any of the preceding claims, characterized in that thedispersing agent is a polyisobutylene succinimide.
 7. Pigmentary pasteaccording to any of the preceding claims, characterized in that thedispersing agent is a polymer obtained by condensing an amine with asuccinic anhydride attached to a saturated or unsaturated hydrocarbonchain.
 8. Pigmentary paste according to any of the preceding claims,characterized in that the weight fraction of the dispersing agent in thepigmentary paste is from 1 to 10% of the total weight of the pigmentarypaste, and preferably of the order of 5%.
 9. Pigmentary paste accordingto any of the preceding claims, characterized in that the pigment isselected from the inorganic pigments, the organic pigments, the nacrepigments, and their mixtures.
 10. Pigmentary paste according to claim 9,characterized in that the inorganic pigments are selected from titaniumdioxide, zinc dioxide, red iron oxide, yellow iron oxide, brown ironoxide, black iron oxide, and their mixtures.
 11. Pigmentary pasteaccording to claim 9, characterized in that the organic pigments areselected from the pure organic pigments or the pigments of the laketype.
 12. Pigmentary paste according to claim 9, characterized in thatthe pigment is the organic pigment D&C Red No
 36. 13. Pigmentary pasteaccording to claim 9, characterized in that the pigment is a lakeselected from the organic lakes of barium, strontium, calcium oraluminium, the lakes based on cochineal carmine, D&C Red No 7 calciumlake, D&C Red No 27 aluminium lake, D&C Red No 21 aluminium lake, FD&CYellow No 5 aluminium lake, FD&C Yellow No 6 aluminium lake, D&C Red No7 and FD&C Blue No 1 aluminium lake, and their mixtures.
 14. Pigmentarypaste according to claim 9, characterized in that the nacre pigments areselected from mica coated with titanium or bismuth oxychloride, titaniummica with iron oxides, titanium mica with ferric blue, titanium micawith chromium oxide, and titanium mica with an organic pigment asdefined in one of claims 11 to
 13. 15. Pigmentary paste according to anyof the preceding claims, characterized in that the anhydrous solvent isselected from the apolar oils.
 16. Pigmentary paste according to any ofthe preceding claims, characterized in that the anhydrous solvent is anapolar hydrocarbon oil, selected from hydrogenated polyisobutene,squalane, the aliphatic hydrocarbons and their mixtures.
 17. Pigmentarypaste according to any of the preceding claims, characterized in thatthe anhydrous solvent is a silicone oil selected from thepolydimethylsiloxanes (PDMS) and the phenylated silicones, such as thephenyl trimethicones, the phenyl dimethicones, the diphenyldimethicones, the diphenyl methyldiphenyl trisiloxanes, and the2-phenylethyl trimethylsiloxysilicates, and their mixtures. 18.Pigmentary paste according to any of the preceding claims, characterizedin that it has a viscosity of 2 to 25 Poises (0.2 to 2.5 Pa.s),preferably of 10 Poises (1 Pa.s) or less, and more preferably of 5poises (0.5 Pa.s) or less, said viscosity being evaluated at ambienttemperature (20-25° C.), with a shearing rate of 200 s⁻¹ .
 19. Cosmeticcomposition containing a cosmetically acceptable medium and a pigmentarypaste such as that defined in one of the preceding claims.
 20. Use of apigmentary paste such as that defined according to one of claims 1 to 18for producing a lipstick.